1. Field of the Invention
The present invention generally relates to a print information processing system using a computer for processing print data such as text data, image data, or graphic data, sending the print data to a printer, and thereby causing the printer to print the print data; a print information processing program executed on the print information processing system; and a recording medium on which the print information processing program is stored.
2. Description of the Related Art
Generally, an operating system (OS) is running on a computer. An OS is basic software that enables efficient operation of a computer. An OS provides an application programming interface (API) that enables programs running on the OS to use functions of the OS and to operate hardware devices. When printing data from a computer where an OS is running to a printer, a special program called printer driver software or a printer driver program (hereafter called “printer driver”) is used. A printer driver is a kind of software program called by an OS.
When a normal program prints data, the program uses a function of the OS via the API and the OS calls a printer driver. A printer driver generates print data for a printer. For example, a printer driver receives input data such as text, images, or graphics from the OS and translates the input data into a print data description language understandable to a printer. Thus, a program (hereafter called “application”) that performs a printing process sends print data such as text data, image data, or graphic data to an OS using an API, and the OS sends the print data to a printer driver. A printer is generally configured to understand one or more print data description languages (hereafter called page description language “PDL”) that are defined by printer manufacturers.
For example, PDLs such as the Print Control Language (PCL) and the PostScript language are well-known. A printer driver translates print data into a PDL that a target printer can understand. Print data translated into a PDL (PDL data) can be printed only on a printer that can understand the PDL. For example, print data in the PCL language cannot be printed on a printer that can understand only the PostScript language.
Also, even printers that can understand the same PDL may have different printing properties such as output resolution and the number of colors (color or monochrome). Therefore, PDL data translated from the same print data may differ depending on the printing properties of a printer. In other words, PDL data for printer A may not be able to be printed on printer B. In a general PDL translation process, print data are translated into PDL data understandable to a printer and also converted to suit the printing properties of the printer. As a result, the portability of the print data becomes very low.
Meanwhile, user needs for printing have become diverse and complicated. A conventional printing method, in which an application sends print data to a printer driver and printing is performed immediately, does not satisfy such needs.
For the above reason, there has been a demand for a highly-portable format for print data output by a printer driver. To improve the portability of print data sent from an application to a printer driver, it is necessary to develop a print data format that is independent of PDLs and printers. If a printer driver can translate print data from an application into portable print data (hereafter called “metadata”) and save the metadata, for example, as a permanent file, the portability of print data can be greatly improved.
When printing metadata, an application sends the metadata to a printer driver, and the printer driver translates the metadata into printer-specific PDL data according to printer properties. Such a method makes it possible to meet various printing needs.
A relevant technology is disclosed, for example, in patent document 1.
[Patent document 1] Japanese Patent Application Publication No. 2001-236186
However, improved portability of metadata files that are independent of PDLs and printers may result in reduced security of print data. In other words, high portability may cause security problems such as alteration of metadata files and stealing of information in metadata files by data analysis. Such security problems do not generally occur in a printing process where an application sends print data to a printer driver, the printer driver translates the print data into PDL data and immediately sends the PDL data to a printer, and the printer prints the PDL data.
Even in the above case, when a computer and a printer are connected via a network, it is possible to steal information by, for example, sniffing packet data. However, information stealing can be prevented by encrypting PDL data during PDL translation.